scholarly journals Antimicrobial susceptibility testing of 230 Helicobacter pylori strains: importance of medium, inoculum, and incubation time.

1997 ◽  
Vol 41 (12) ◽  
pp. 2634-2639 ◽  
Author(s):  
S H Hartzen ◽  
L P Andersen ◽  
A Bremmelgaard ◽  
H Colding ◽  
M Arpi ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Incubation Time ◽  
Susceptibility Testing ◽  
Development Of Resistance ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
Agar Dilution ◽  
Horse Blood ◽  
Preliminary Study ◽  
H Pylori

No standardized method of susceptibility testing for Helicobacter pylori is currently available, so before a large agar dilution study comprising 230 H. pylori strains belonging to more than 80 genetically different groups was initiated, we performed a relatively small preliminary study to determine the influences of medium, inoculum density, and incubation time. Seven media were investigated and were primarily evaluated on the basis of their abilities to support growth both semiquantitatively and qualitatively; Iso-Sensitest agar supplemented with 10% horse blood was found to be well suited for the purpose; this was closely followed by Mueller-Hinton agar with 10% horse blood, Mueller-Hinton with 10% sheep blood, and finally, 7% lysed horse blood agar. Investigations of two inoculum densities and two incubation times resulted in recommendations for the use of 10(9) CFU/ml (10[6] CFU/spot) as the inoculum and 72 h as the incubation time. A modest inoculum effect was noted for amoxicillin and metronidazole. By the methodology derived from our preliminary study, the susceptibilities of 230 H. pylori strains to six antibiotics were subsequently determined. The results were generally in accord with those of others, and apart from metronidazole, the MIC of which for approximately 25% of the strains tested was >8 microg/ml, resistance was low in Denmark. The situation might, however, quickly change when and if the number of indications for antibiotic therapy for H. pylori infections increase. Consequently, susceptibility testing of all H. pylori strains is recommended in order to survey the development of resistance, and in our hands the described methodology was relatively easy to perform and the results were easy to read.

E-Test or Agar Dilution for Metronidazole Susceptibility Testing of Helicobacter Pylori: Importance of the Prevalence of Metronidazole Resistance

2021 ◽  
Author(s):  
Jinnan Chen ◽  
Yu Huang ◽  
Zhaohui Ding ◽  
Xiao Liang ◽  
Hong Lu
Keyword(s):  
Helicobacter Pylori ◽  
Susceptibility Testing ◽  
Resistance Rate ◽  
Test Method ◽  
Major Error ◽  
Metronidazole Resistance ◽  
Agar Dilution ◽  
H Pylori ◽  
High Level ◽  
Level Resistance

Abstract Background: A number of studies have shown that E-test overestimated the presence of Helicobacter pylori (H. pylori) resistance compared to agar dilution.Objective: The purpose of this study was to explore whether E-test could be an alternative for agar dilution to detect the metronidazole susceptibility of H. pylori.Method: E-test and agar dilution were used to assess susceptibility of H. pylori to metronidazole, clarithromycin and levofloxacin in 281 clinical isolates obtained from China where resistance was high. Cohen kappa analysis, McNemar test, essential and categorical agreement analysis were performed for these two methods. Results: Overall, the result of E-test showed similar prevalence of resistance rate to all antibiotics compared with agar dilution. The essential agreement (EA) of E-test method and agar dilution in the evaluation susceptibility of H. pylori to clarithromycin and levofloxacin were moderate, with 89.0% and 79.7% respectively, but only 45.9% for metronidazole. Results showed categorical agreement (CA) between E-test and agar dilution were 100% for both clarithromycin and levofloxacin. As for metronidazole, the CA was 98.7%, no major error was identified, and rate of very major error was 1.8%.Conclusion: E-test can be an alternative method to detect the metronidazole susceptibility of H. pylori in regions where high-level resistance is common.

scholarly journals Helicobacter pylori: Primary Susceptibility to Clarithromycin in vitro in Nova Scotia

1997 ◽  
Vol 11 (4) ◽  
pp. 298-300 ◽  
Author(s):  
Linda M Best ◽  
David JM Haldane ◽  
Gregory S Bezanson ◽  
Sander JO Veldhuyzen
Keyword(s):  
Helicobacter Pylori ◽  
Nova Scotia ◽  
Antimicrobial Agents ◽  
Primary Resistance ◽  
Susceptibility Data ◽  
Mueller Hinton ◽  
Agar Diffusion Test ◽  
Mueller Hinton Agar ◽  
H Pylori

Resistance to antimicrobial agents is a major determinant of the efficacy of regimens to eradicateHelicobacter pylori. Clarithromycin (CLA) has become one of the most commonly used antibiotics for treatment ofH pyloriinfection. In this study, the rate of primary resistance to CLA inH pyloriisolated from patients was determined. One hundred sixty-two strains were recovered from patients before treatment. Strains were grown and inoculated onto Mueller-Hinton agar with 7% sheep blood. CLA epsilometer gradient agar diffusion test (E test) strips were used to test for susceptibility. Appropriate control organisms were tested to validate the assay. Plates were incubated at 37°C in a microaerophilic atmosphere for up to five days. E test results were easy to interpret. Strains were considered resistant if the minimum inhibitory concentration (MIC) was 2 µg/mL or greater. Three strains were resistant (two strains with MIC 8 µg/mL and one strain with MIC 12 µg/mL), and 159 strains were sensitive (MICs ranged from less than 0.016 to 0.38 µg/mL). Ninety per cent of the strains had MICs of 0.023 µg/mL. Primary resistance was 1.8%. These susceptibility data support the use of CLA for the treatment ofH pyloriin the Nova Scotia population.

scholarly journals In vitro susceptibilities of Bordetella pertussis and Bordetella parapertussis to four fluoroquinolones (levofloxacin, d-ofloxacin, ofloxacin, and ciprofloxacin), cefpirome, and meropenem.

1996 ◽  
Vol 40 (3) ◽  
pp. 807-808 ◽  
Author(s):  
J E Hoppe ◽  
E Rahimi-Galougahi ◽  
G Seibert
Keyword(s):  
Bordetella Pertussis ◽  
Clinical Isolates ◽  
Bordetella Parapertussis ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
Agar Dilution ◽  
Horse Blood

The in vitro activities of levofloxacin, ofloxacin, d-ofloxacin, ciprofloxacin, cefpirome, and meropenem against 34 clinical isolates each of Bordetella pertussis and Bordetella parapertussis were determined by agar dilution on Mueller-Hinton agar supplemented with 5% horse blood. Levofloxacin was as active as ciprofloxacin against both species (MIC, 0.06 microgram/ml) and more active than ofloxacin and d-ofloxacin. Cefpirome was more active against B. pertussis (MIC, 1.0 microgram/ml) than against B. parapertussis (MIC, > 2 micrograms/ml), while the reverse was true for meropenem (MIC, 2.0 micrograms/ml against B. pertussis and 1.0 microgram/ml against B. parapertussis).

scholarly journals Antimicrobial Susceptibility of Helicobacter pylori Determined by the E Test Using Tetrazolium Egg Yolk Agar

1998 ◽  
Vol 36 (9) ◽  
pp. 2784-2785 ◽  
Author(s):  
Yanet Valdez ◽  
Billie Velapatiño ◽  
Robert H. Gilman ◽  
Vilma Gutierrez ◽  
Carlos León
Keyword(s):  
Helicobacter Pylori ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Agar Medium ◽  
Egg Yolk ◽  
Blood Agar ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Agar Dilution ◽  
H Pylori

Metronidazole and tetracycline E tests were compared to an agar dilution method for the antimicrobial susceptibility testing ofHelicobacter pylori. Sixteen strains were tested by using tetrazolium egg yolk (TEY) agar. The characteristic E test inhibition ellipse was clearer on TEY agar than on standard blood agar and gave results comparable to those of the agar dilution test. The use of TEY medium is preferable to that of blood agar medium in E test MIC determinations for H. pylori.

scholarly journals Subpopulations of Helicobacter pyloriAre Responsible for Discrepancies in the Outcome of Nitroimidazole Susceptibility Testing

1999 ◽  
Vol 43 (6) ◽  
pp. 1484-1486 ◽  
Author(s):  
E. J. van der Wouden ◽  
A. de Jong ◽  
J. C. Thijs ◽  
J. H. Kleibeuker ◽  
A. A. van Zwet
Keyword(s):  
Helicobacter Pylori ◽  
Susceptibility Testing ◽  
Clinical Isolates ◽  
Disk Diffusion ◽  
Agar Dilution ◽  
H Pylori

ABSTRACT Metronidazole susceptibility testing by E test was compared to that by disk diffusion for 263 Helicobacter pylori isolates and to that by breakpoint agar dilution for 90 H. pyloriisolates. In 5% and 6% of the cases, respectively, results were discrepant. For each of 52 clinical isolates an E test was performed on 10 separate colonies. Subpopulations of resistant and susceptible bacteria were found in five cases. From three isolates, each colony was subcultured and tested up to 10 times. All but 1 of 292 tests showed the same result. We conclude that the E test is reliable and that subpopulations are responsible for discordant results.

scholarly journals In Vitro Susceptibilities of Bordetella pertussis and Bordetella parapertussis to Two Ketolides (HMR 3004 and HMR 3647), Four Macrolides (Azithromycin, Clarithromycin, Erythromycin A, and Roxithromycin), and Two Ansamycins (Rifampin and Rifapentine)

1998 ◽  
Vol 42 (4) ◽  
pp. 965-966 ◽  
Author(s):  
Jörg E. Hoppe ◽  
André Bryskier
Keyword(s):  
Bordetella Pertussis ◽  
Active Compound ◽  
Bordetella Parapertussis ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
Agar Dilution ◽  
Horse Blood ◽  
Erythromycin A

ABSTRACT When tested by agar dilution on Mueller-Hinton agar supplemented with 5% horse blood, the ketolides HMR 3004 and HMR 3647 were slightly more active (MIC at which 90% of the isolates were inhibited [MIC90], 0.03 μg/ml) against Bordetella pertussis than azithromycin, clarithromycin, erythromycin A, and roxithromycin. Azithromycin (MIC90, 0.06 μg/ml) was the most active compound against B. parapertussis. Rifampin and rifapentine were considerably less active.

scholarly journals Comparison of Activity of 10 Antibiotics Against Clinical Strains ofHelicobacter pyloriby Three Different Techniques

1998 ◽  
Vol 12 (3) ◽  
pp. 181-185 ◽  
Author(s):  
K Weiss ◽  
M Laverdiere ◽  
C Restieri
Keyword(s):  
Resistance Rate ◽  
Diffusion Method ◽  
Dilution Technique ◽  
Disk Diffusion Method ◽  
Clinical Strains ◽  
Metronidazole Resistance ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
Agar Dilution ◽  
H Pylori

The authors determined the susceptibility of 55 single clinical strains ofHelicobacter pyloriisolated in the Montreal area to 10 antibiotics by three different methods - an agar dilution technique considered to be the gold standard, a disk diffusion method and the E-test. Testing was performed on Mueller-Hinton agar supplemented with 10% sheep blood; plates were incubated at 37°C for 72 h in a microaerophilic atmosphere. The metronidazole resistance rate is about 11% in the Montreal area. Macrolides are very active againstH pyloriisolates, with few variations in activity between older and newer molecules. Correlation among different methods was not as good as reported in the literature for metronidazole.

Laboratory proficiency in susceptibility testing of Helicobacter pylori using agar dilution and E test methods

2001 ◽  
Vol 120 (5) ◽  
pp. A586-A587
Author(s):  
L BEST ◽  
S JO ◽  
V VANZANTEN ◽  
D HALDANE ◽  
V LOO ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Susceptibility Testing ◽  
Test Methods ◽  
Agar Dilution

scholarly journals Intracellular Presence of Helicobacter pylori and Its Virulence-Associated Genotypes within the Vaginal Yeast of Term Pregnant Women

2021 ◽  
Vol 9 (1) ◽  
pp. 131
Author(s):  
Kimberly Sánchez-Alonzo ◽  
Lillian Matamala-Valdés ◽  
Cristian Parra-Sepúlveda ◽  
Humberto Bernasconi ◽  
Víctor L. Campos ◽  
...  
Keyword(s):  
Risk Factors ◽  
Helicobacter Pylori ◽  
Virulence Genes ◽  
Yeast Cells ◽  
Bacterial Identification ◽  
Infection Risk Factors ◽  
Horse Blood ◽  
Total Dna ◽  
H Pylori ◽  
Total Yeast

Background: Helicobacter pylori transmission routes are not entirely elucidated. Since yeasts are postulated to transmit this pathogen, this study aimed to detect and genotype intracellular H. pylori harbored within vaginal yeast cells. Methods: A questionnaire was used to determine risk factors of H. pylori infection. Samples were seeded on Sabouraud Dextrose Agar and horse blood-supplemented Columbia agar. Isolated yeasts were identified using and observed by optical microscopy searching for intra-yeast H. pylori. Total yeast DNA, from one random sample, was extracted to search for H. pylori virulence genes by PCR and bacterial identification by sequencing. Results: 43% of samples contained yeasts, mainly Candida albicans (91%). Microscopy detected bacteria such as bodies and anti-H. pylori antibodies binding particles in 50% of the isolated yeasts. Total DNA extracted showed that 50% of the isolated yeasts were positive for H. pylori 16S rDNA and the sequence showed 99.8% similarity with H. pylori. In total, 32% of H. pylori DNA positive samples were cagA+ vacAs1a vacAm1 dupA−. No relationship was observed between possible H. pylori infection risk factors and vaginal yeasts harboring this bacterium. Conclusion: H. pylori having virulent genotypes were detected within vaginal yeasts constituting a risk for vertical transmission of this pathogen.

scholarly journals Applicability and performance of EUCAST’s rapid antimicrobial susceptibility testing (RAST) on primarily sterile body fluids in blood culture bottles in laboratory routine with total lab automation

2021 ◽  
Author(s):  
Jasmin Kaur Jasuja ◽  
Stefan Zimmermann ◽  
Irene Burckhardt
Keyword(s):  
Blood Culture ◽  
Susceptibility Testing ◽  
Reference Method ◽  
Body Fluids ◽  
E Coli ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
And Performance ◽  
Sterile Body Fluids ◽  
Better Than

AbstractOptimisation of microbiological diagnostics in primarily sterile body fluids is required. Our objective was to apply EUCAST’s RAST on primarily sterile body fluids in blood culture bottles with total lab automation (TLA) and to compare results to our reference method Vitek2 in order to report susceptibility results earlier. Positive blood culture bottles (BACTEC™ Aerobic/Anaerobic/PEDS) inoculated with primarily sterile body fluids were semi-automatically subcultured onto Columbia 5% SB agar, chocolate agar, MacConkey agar, Schaedler/KV agar and Mueller-Hinton agar. On latter, cefoxitin, ampicillin, vancomycin, piperacillin/tazobactam, meropenem and ciprofloxacin were added. After 6 h, subcultures and RAST were imaged and MALDI-TOF MS was performed. Zone sizes were digitally measured and interpreted following RAST breakpoints for blood cultures. MIC values were determined using Vitek2 panels. During a 1-year period, 197 Staphylococcus aureus, 91 Enterococcus spp., 38 Escherichia coli, 11 Klebsiella pneumoniae and 8 Pseudomonas aeruginosa were found. Categorical agreement between RAST and MIC was 96.5%. Comparison showed no very major errors, 2/7 (28.6%) and 1/7 (14.3%) of major errors for P. aeruginosa and meropenem and ciprofloxacin, 1/9 (11.1%) for K. pneumoniae and ciprofloxacin, 4/69 (7.0%) and 3/43 (5.8%) for Enterococcus spp. and vancomycin and ampicillin, respectively. Minor errors for P. aeruginosa and meropenem (1/8; 12.8%) and for E. coli and ciprofloxacin (2/29; 6.5%) were found. 30/550 RAST measurements were within area of technical uncertainty. RAST is applicable and performs well for primarily sterile body fluids in blood culture bottles, partially better than blood-based RAST. Official EUCAST evaluation is needed.

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